a radio station can broadcasts in all directions to a distance of 60 mi. what is the area in which the station can be heard
2 answers:
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Answer:
a) The standard error would be of 8.58 pounds.
b) The margin of error is 14.11 pounds.
c) The 90% confidence interval for the population mean is between 232.89 pounds and 261.11 pounds
Step-by-step explanation:
a.What is the standard error?
The standard error is
In which is the standard deviation of the population and n is the size of the sample. So
The standard error would be of 8.58 pounds.
b.What is the margin of error at 90% confidence?
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
So it is z with a pvalue of , so
Now, find the margin of error M as such
The margin of error is 14.11 pounds.
c. Using my sample of 30, what would be the 90% confidence interval for the population mean?
Lower bound: Sample mean subtracted by the margin of error.
247 - 14.11 = 232.89 pounds
Upper bound
247 + 14.11 = 261.11 pounds
The 90% confidence interval for the population mean is between 232.89 pounds and 261.11 pounds
To apply the quadratic formula, the right side must be equal to 0.
Now you can apply the quadratic formula
to find the solution for w.
(The quadratic formula is highly unnecessary in this problem, however. You could easily divide all values by 2 to get w²-14w+49=0, which factors into (w-7)²=0, for which 7 is the only solution which puts a factor of the quadratic equal to 0.)
Now you can apply the quadratic formula
(The quadratic formula is highly unnecessary in this problem, however. You could easily divide all values by 2 to get w²-14w+49=0, which factors into (w-7)²=0, for which 7 is the only solution which puts a factor of the quadratic equal to 0.)